Standard image projection setups are limited to projecting an image to a projection surface whilst leaving the surrounding area dark. PCT/WO 2004/112386 A1 describes a device for illuminating the area surrounding a projection screen on the basis of the image data. This illumination allows for more pleasant viewing and generates the sensation of the image being extended beyond the actual projection area. Also, US 2005/004164 A1 describes a device which causes areas in the vicinity of the projection screen to be illuminated on the basis of the image displayed. This arrangement makes use of the fact that a human viewer is only able to perceive details inside a region given by a narrow angle about his current viewing direction. Accordingly, illuminated areas outside of the normal viewing angle are sufficient to augment the sense of presence of the video projected onto the projection screen.
However, these devices require either specifically designed projection units or at least a control signal derived from the video signal itself.
It is an object of the invention to provide a simple way to illuminate the surrounding of a projection surface on the basis of the image projected onto that surface, without having to intercept the video signal and without requiring alterations to the projection unit.